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Randomized Controlled Trial
. 2010 Jul 27;4(7):e767.
doi: 10.1371/journal.pntd.0000767.

Randomised controlled double-blind non-inferiority trial of two antivenoms for saw-scaled or carpet viper (Echis ocellatus) envenoming in Nigeria

Isa S Abubakar  1 , Saidu B Abubakar, Abdulrazaq G Habib, Abdulsalam Nasidi, Nandul Durfa, Peter O Yusuf, Solomon Larnyang, John Garnvwa, Elijah Sokomba, Lateef Salako, R David G Theakston, Ed Juszczak, Nicola Alder, David A Warrell; Nigeria-UK EchiTab Study Group
Affiliations
Randomized Controlled Trial

Randomised controlled double-blind non-inferiority trial of two antivenoms for saw-scaled or carpet viper (Echis ocellatus) envenoming in Nigeria

Isa S Abubakar et al. PLoS Negl Trop Dis. .

Abstract

Background: In West Africa, envenoming by saw-scaled or carpet vipers (Echis ocellatus) causes great morbidity and mortality, but there is a crisis in supply of effective and affordable antivenom (ISRCTN01257358).

Methods: In a randomised, double-blind, controlled, non-inferiority trial, "EchiTAb Plus-ICP" (ET-Plus) equine antivenom made by Instituto Clodomiro Picado was compared to "EchiTAb G" (ET-G) ovine antivenom made by MicroPharm, which is the standard of care in Nigeria and was developed from the original EchiTAb-Fab introduced in 1998. Both are caprylic acid purified whole IgG antivenoms. ET-G is monospecific for Echis ocellatus antivenom (initial dose 1 vial) and ET-Plus is polyspecific for E. ocellatus, Naja nigricollis and Bitis arietans (initial dose 3 vials). Both had been screened by pre-clinical and preliminary clinical dose-finding and safety studies. Patients who presented with incoagulable blood, indicative of systemic envenoming by E. ocellatus, were recruited in Kaltungo, north-eastern Nigeria. Those eligible and consenting were randomly allocated with equal probability to receive ET-Plus or ET-G. The primary outcome was permanent restoration of blood coagulability 6 hours after the start of treatment, assessed by a simple whole blood clotting test repeated 6, 12, 18, 24 and 48 hr after treatment. Secondary (safety) outcomes were the incidences of anaphylactic, pyrogenic and late serum sickness-type antivenom reactions.

Findings: Initial doses permanently restored blood coagulability at 6 hours in 161/194 (83.0%) of ET-Plus and 156/206 (75.7%) of ET-G treated patients (Relative Risk [RR] 1.10 one-sided 95% CI lower limit 1.01; P = 0.05). ET-Plus caused early reactions on more occasions than did ET-G [50/194 (25.8%) and 39/206 (18.9%) respectively RR (1.36 one-sided 95% CI 1.86 upper limit; P = 0.06). These reactions were classified as severe in 21 (10.8%) and 11 (5.3%) of patients, respectively.

Conclusion: At these doses, ET-Plus was slightly more effective but ET-G was slightly safer. Both are recommended for treating E. ocellatus envenoming in Nigeria.

Trial registration: Current Controlled Trials ISRCTN01257358.

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Conflict of interest statement

The authors have declared that no competing interests exist.

Figures

Figure 1
Figure 1. Flow of participants through the trial.
See this image and copyright information in PMC

References

    1. Warrell DA, Arnett C. The importance of bites by the saw-scaled or carpet viper (Echis carinatus) in Nigeria. Quart J Med. 1976;46:33–62. - PubMed
    1. Trape JF, Pison G, Guyavarch E, Mane Y. High mortality from snakebite in south-eastern Senegal. Trans R Soc Trop Med Hyg. 2001;95:420–423. - PubMed
    1. Visser LE, Kyei-Faried S, Belcher DW, Geelhoed DW, van Leeuwen JS, et al. Failure of a new antivenom to treat Echis ocellatus snake bite in rural Ghana: the importance of quality surveillance. Trans R Soc Trop Med Hyg. 2008;102:445–450. - PubMed
    1. Chippaux JP, Lang J, Amadi-Eddine S, Fagot P, Le Mener V. Short report: treatment of snake envenomations by a new polyvalent antivenom composed of highly purified F(ab)2: results of a clinical trial in northern Cameroon. Am J Trop Med Hyg. 1999;61:1017–1018. - PubMed
    1. Chippaux JP, Massougbodji A, Stock RP, Alagon A Investigators of African Antivipmyn in Benin. Clinical trial of an F(ab')2 polyvalent equine antivenom for African snake bites in Benin. Am J Trop Med Hyg. 2007;77:538–546. - PubMed

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